#include <ros/ros.h>
#include <visualization_msgs/Marker.h>
#include <cmath>
int main(int argc, char **argv)
{
    ros::init(argc, argv, "points_and_lines");
    ros::NodeHandle n;
    ros::Publisher marker_pub = n.advertise<visualization_msgs::Marker>("visualization_marker", 10);
    ros::Rate r(30);
    float f = 0.0;
    while (ros::ok())
    {
        //创建一个 visualization_msgs/Marker消息，并且初始化所有共享的数据。消息成员默认为0，仅仅设置位姿成员w。
        visualization_msgs::Marker points, line_strip, line_list;
        points.header.frame_id = line_strip.header.frame_id = line_list.header.frame_id = "/my_frame";
        points.header.stamp = line_strip.header.stamp = line_list.header.stamp = ros::Time::now();
        points.ns = line_strip.ns = line_list.ns = "points_and_lines";
        points.action = line_strip.action = line_list.action = visualization_msgs::Marker::ADD;
        points.pose.orientation.w = line_strip.pose.orientation.w = line_list.pose.orientation.w = 1.0;

        //分配三个不同的id到三个markers。points_and_lines名称空间的使用确保彼此不会相互冲突。
        points.id = 0;
        line_strip.id = 1;
        line_list.id = 2;
        //设置marker类型到 POINTS, LINE_STRIP 和 LINE_LIST
        points.type = visualization_msgs::Marker::POINTS;
        line_strip.type = visualization_msgs::Marker::LINE_STRIP;
        line_list.type = visualization_msgs::Marker::LINE_LIST;
        // scale成员对于这些marker类型是不同的,POINTS marker分别使用x和y作为宽和高，然而LINE_STRIP和LINE_LIST marker仅仅使用x，定义为线的宽度。单位是米。
        points.scale.x = 0.2;
        points.scale.y = 0.2;
        // LINE_STRIP/LINE_LIST markers use only the x component of scale, for the line width
        line_strip.scale.x = 0.1;
        line_list.scale.x = 0.1;
        // 点为绿色
        points.color.g = 1.0f;
        points.color.a = 1.0;
        // Line strip 是蓝色
        line_strip.color.b = 1.0;
        line_strip.color.a = 1.0;
        // Line list 为红色
        line_list.color.r = 1.0;
        line_list.color.a = 1.0;

        //使用正弦和余弦生成螺旋结构。POINTS和LINE_STRIP markers都仅仅需要1个点作为每个顶点，然而LINE_LIST marker需要2个点 。
        for (uint32_t i = 0; i < 100; ++i)
        {
            float y = 5 * sin(f + i / 100.0f * 2 * M_PI);
            float z = 5 * cos(f + i / 100.0f * 2 * M_PI);
            geometry_msgs::Point p;
            p.x = (int32_t)i - 50;
            p.y = y;
            p.z = z;
            points.points.push_back(p);
            line_strip.points.push_back(p);
            // The line list needs two points for each line
            line_list.points.push_back(p);
            p.z += 1.0;
            line_list.points.push_back(p);
        }
        //发布各个markers
        marker_pub.publish(points);
        marker_pub.publish(line_strip);
        marker_pub.publish(line_list);
        r.sleep();
        f += 0.04;
    }
}
